Audio mixer



FIG. 1 is a perspective view of an audio mixer showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a side elevational view thereof;

FIG. 5 is an opposite side elevational view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines and unshaded areas form no part of the claimed design. 

CLAIM The ornamental design for an audio mixer, as shown and described. 